Reducing composition useful for textile printing and other purposes



Patented May 14, 1940 PATENT oF icE;

REDUCING COMPOSITION USEFUL FOR TEXTILE PRINTING AND OTHER PUR- POSES Henry PapinLPawtucket, R. 1., assignor to Warwick Chemical (30., West Warwick, R. I., a corporation. of'Rhode Island N0 Drawing. Application August 16, 1938, Serial No. 225,144

9 Claims.

The present invention relates to'reducing coinpositions and particularly relates to reducin compositions which may be utilized in connection Withtextile printing and dyeing procedures and for other purposes where a predetermined oxidation-reduction potential. is to be maintained.

In certain typesof printing known to those skilled in the arts as discharge printing, it is the custom to dye the cloth or fabric with certain types of dyestuffs which may be reduced to a colorless, soluble form and to imprint or place paste or viscous liquid containing a soluble reducing agent in a suitable design or pattern upon F thedyed fabric andsubsequently to dry, age and wash, whereby a white figure or design may be produced on the colored cloth. Or if it is desired, a colored figure or design maybe produced in-- stead of the white figure or design by addition of suitable colors, not aifected by the reducing agent, to the printing paste or liquid. For instance, a dark navy blue shade may be dyed on a fabric and then discharged to a clear White de sign or merely to a light blue by using less reducing agent. Or in the event'that it may be desirable to imprint a black figure on a navy blue ground the black color or pigment may be mixed with the printing composition containing the re ducing agent.

It is also customary in many cases to print with a composition containing a normal insoluble dyestuff which has been reduced to a soluble or leuco condition by inclusion in the printing paste of a reducing agent. After printing the dye and reducing agent are oxidized with resultant deposition of the insoluble. dyestufi. All dyestuffs of this character are hereinafter referred to in the specification and claims as vat dyes or vat coloring matters.

Hydrosulphites. and sulphoxylates are widely used as such reducing agents in textile printing procedures, particularly to cause development of color or discharge of color in connection with indigoid, anthraquinone, carbazol, sulphur and vat coloring matters in general. These hydrosulphites or sulphoxylates also are used in other processes and industries because of their reducing characteristics.

However; hydrosulphites and sulphoxylates and their derivativeshave many disadvantageous characteristics. They are not most stable compounds and tend to decompose or change in strength standing in air and/or at elevated temperatures. Moreover, they must be taken up in solution or employed in combinations with quantities of hygroscopic materials or agents which will maintain a moist condition when utilized in various textile printing or discharge procedures. Hygroscopic agents, such as glycerol, glycol and sugars increase the cost of processing the textile material.

It is, therefore, amongthe objects of the present invention to provide improved reducing compositions of the character above described compounded which may be more conveniently used in connection with dyeing and printing of textiles or for many other purposes where the inclusion of a reducing agent has been found desirable or necessary.

Other objects will be apparent or will become obvious during the course of the following specification.

In accomplishing the above objects, it has been found suitable to utilize hydroxy-aldehyde or hydroxy ketone compounds, preferably containing from three to five carbon atoms and having the hydroxy and the aldo or ketone groups attached to adjacent carbon atoms.

Although compounds having an aliphatic chain with a larger number of carbon atoms may also be employed in certain circumstances, it is preferred to have a straight chain of 3 to 6 carbon atoms with a plurality of keto, aldo and/or hydroxy groups attached to successive carbon atoms and at least two hydroXy and one keto or aldo group.

The compounds which have been found to function most satisfactorily are di-hydroxy keto or aldo propane, although it is also possible to utilize di-hydroxy di-keto or di-aldo-butanes, pentanes or hexanes.

Among the preferred compounds are symmetrical di-hydroxy acetone which may be readily prepared from sugars or sucrose by treatment under pressure with tartaric acid or another organic acid in a glass lined autoclave at a pressure up to 7 to 10 atmospheres and ata low temperature of 30 to 40 C. The reaction mixture produced may be directly utilized in combination with gums, dyes and other ingredients to form a textile printingcomposition.

Di-hydroxy acetone is particularly suitable in.- asmuch as it forms a stable aqueous "solution of about 40 to 60% concentration, with an optimum of about concentration, which will not take up water from the air nor evaporate and which solution may be stored for long periods of time and utilized when convenient without special storage apparatus.

The dihydroxy acetone is quite different from diacetone alcohol which latter is a solvent and is not particularly a reducing agent.

The dihydroxy acetone tends to establish an equilibrium with its enolic compound, glyceric aldehyde and it is probable that solutions of dihydroxy acetone may contain both the acetone and said aldehyde.

The dihydroxy acetone, if desired, may be stabilized by forming combinations of it which will be readily broken upon usage of the compounds or its compositions as a reducing agent.

The di-hydroxy acetone'may be used in printing pastes and in dye baths as a reducing agent and it may be very conveniently combined with vat colors selected from the group consisting of indigoid colors, sulphur, anthraquinone colors and carbazol colors and with thickening agents such as British gum, gum shiraz, gum tragacanth dextrin, gum arabic, starch, pectin, methyl cellulose without any undesirable efiect upon the properties of such agents.

Although di-hydroxy acetone has a relatively higher reducing action and much higher in many respects than hydrosulphites or sulphoxylates, nevertheless, it is not oxidized by air and does not substantially lose its reducing power, although it be exposed to air over long periods of time. This is particularly advantageous because in the printing operations it is at times necessary for the goods to lay over between the printing and ageing operations. Where sulphoxylates and hydrosulphites are used as the reducing medium this laying over causes a variation in the shade, because they may oxidize prematurely.

The di-hydroxy acetone is specially advantageous since it has a much greater potential reducing power than hydrosulphites and sulphoxylatesand at the same time will reduce at a slower rate.

The di-hydroxy acetone may also be utilized at a Wide variety of pI-Is and alkaline materials such as sodium or potassium carbonate, potassium and sodium hydroxides, or mixtures of each and potash and soda ash may be included in the printing composition without any untoward effect.

It is also readily possible to include moistening agents such as glycerin, glycols, sugars, and so forth, in the printing composition without aifecting the reducing agent.

Among the suitable base compositions which may be utilized for carrying the unreduced or pre-reduced color and the di-hydroxy acetone is one containing about four pounds of British gum, two pounds of cornstarch, A; gallon of glycerol and 2 /4 pounds of potassium carbonate which is made up to three gallons with water.

The amount of water may be readily controlled to determine the final viscosity or pasty character of the mixture.

For example, to such a composition there may be added from 5 to 20% of a 50% solution of dihydroxy acetone and a suitable amount of vat color to obtain the desired shade or tint or depth of color.

The printing paste may be kept for a long time with assurance that the di-hydroxy acetone will not cause any undesirable disintegration or deterioration therein.

The di-hydroxy acetone may be also combined with sulphurous acid or its normal or acid sodium or potassium or even ammonium salts to form suitable reducing compounds and derivatives of it may also be formed by combining it with acids, such as sulphurous, or the corresponding salts, in the presence of zinc or other metals to form suitable metallic reducing salts.

It is also possible to form condensation products with formaldehyde by merely heating; or condensation products may be formed by permitting the di-hydroxy acetone to stand in the presence of suitable condensing agents. The resulting condensation products or polymers may also be utilized by themselves or in combination with sulphurous acid or other compounds.

The di-hydroxy acetone may also be utilized in connection with bleaching compositions, washing compounds, foodstufis, coating compositions, leather treating compositions, paper impregnating compositions and in many other connections where it is desirable to have a reducing agent present during a course of treatment.

- Although di-hydroxy acetone may be utilized by itself in printing pastes, as above stated, it also may be used to replace part or all of the hydrosulphite or sulpho-xylate and it may be used in combination with hydrosulphites, sulphoxylates, their formaldehyde derivatives or zinc, calcium or magnesium salts of such derivatives in substantially equal parts by Weight.

It is to be understood that many changes in the proportions, ingredients and treating conditions may be made without departing from the scope of the invention and it is intended to include all such alternative modifications and variations as come within the scope of the appended claims.

What is claimed is: I

1. As a printing composition comprising a vat color, a thickening agent and a hydroxy acetone.

2. A process of printing textiles which comprises treating such textiles with a printing composition containing dihydroxy acetone and a vat color.

3. A process of printing textiles which comprises treating such textiles with a printing composition containing dihydroxy acetone, a vat color, a thickening agent and potassium carbonate.

4. A vat dye composition containing dihydroxy acetone, a thickening agent and a vat dye.

5. A vat dye composition containing dihydroxy acetone, a thickening agent, a vat dye and a reducing sulphur salt.

6. A vat dye composition comprising a vat dye dihydroxy acetone, British gum, cornstarch, glycerol and potassium carbonate.

7. A vat dyeing composition comprising a vat dye and a hydroxy acetone as a reducing agent for said vat dye.

8. A process of reducing vat dyes which comprises reacting said vat dyes in the presence of aqueous medium with a hydroxy acetone.

9. A vat dyeing composition comprising a vat dye and a reducing agent including the reaction mixture resulting from the pressure treatment of an aqueous solution of a sugar with an organic acid.

HENRY PAPIN'I. 

